Wave coil filter assembly

ABSTRACT

A filter assembly including a continuous resilient cylindrical helical filter coil having flat top and bottom surfaces with each coil including a regular sinusoidal shape having multiple peaks and troughs with the flat top and bottom surfaces of adjacent coils in contact and a drive engaging the helical coil moving adjacent coils relative to each other to modify the volume of the loop-shaped filter pores and control the pore size. In one embodiment, the drive rotates a coil relative to the remaining coils to bring the sinusoidal waves of adjacent coils into and out of registry to decrease or increase the size of the filter pores. In another embodiment, the drive compresses the filter coil to change the size of the filter pores.

RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. Ser. No.11/531,986, filed Sep. 14, 2006, which application was a divisionalapplication of U.S. Ser. No. 10/863,798, filed Jun. 8, 2004, now U.S.Pat. No. 7,122,123 issued Oct. 17, 2006, which was a divisionalapplication of U.S. Ser. No. 09/931,510, filed Aug. 16, 2001, now U.S.Pat. No. 6,761,270 issued Jul. 13, 2004, which claims priority to U.S.Provisional Patent Application No. 60/225,895, filed Aug. 17, 2000.

BACKGROUND OF THE INVENTION

1) Field of the Invention

The subject invention generally relates to a filter assembly and methodof filtering utilizing the filter assembly to filter a fluid. Morespecifically, the subject invention relates to an adjustable filterassembly including a filter element and filtration apertures that aredefined between crests and troughs of adjacent wave coils of the filterelement wherein the filtration apertures are adjustable.

2) Description of Related Art

Spring filters are known in the art. Helically- or spirally-wound springfilters are also known in the art. Examples of such conventional springfilters are disclosed in U.S. Pat. Nos. 4,113,000; 4,199,454; and5,152,892. Conventional spring filters, including the helically- andspirally-wound spring filters disclosed in the above-referenced patents,are deficient for various reasons. For instance, certain conventionalspring filters are not adjustable. Other conventional spring filters arenot easily adjustable and are not easily manufactured. As one specificexample, the conventional spring filter disclosed in the '892 patent isdeficient because the entire coil of this conventional spring filter,which is made up of a plurality of individual flat coils, is extremelyweak having a k factor of about zero. As a result, filtration gaps, orfiltration apertures, cannot be maintained between the individual flatcoils when the spring filter is vertically-oriented. This conventionalspring filter is also particularly difficult to manufacture. Morespecifically, this conventional spring filter requires that theindividual flat coils of the filter be manufactured such that thefiltration apertures, between adjacent flat coils progressively increasein size and pitch which, as understood by those skilled in the art, is aparticularly cumbersome requirement. This conventional spring filterfurther requires that projections be machined into each coil to maintaina minimum filtration aperture between adjacent coils of the filter, thusinvolving additional machining requirements and even limits on size ofthe spring filter.

Due to the deficiencies identified in the spring filters of the priorart, including those set forth above, it is desirable to implement anadjustable filter assembly that is ideal to manufacture and thatuniquely defines a filtration aperture between adjacent coils of afilter element for optimum filtering of fluids due to the adjustabilityof the filtration aperture. It is also desirable that the adjustablefilter assembly according to the subject invention can be easilymanufactured into a wide range of sizes and stiffnesses of the filterelement.

SUMMARY OF THE INVENTION AND ADVANTAGES

A filter assembly for filtering fluids, including residential,industrial and agricultural waste and sludges to recover potable water,oils, hydrocarbons, alcohols, cleaning fluids, waste gases, etc. Thefilter assembly of this invention comprises a continuous resilientcylindrical helical coil including a plurality of interconnectedcircular coils each having a plurality of sinusoidal cycles in thedirection of the helix, including opposed flat top and bottom surfaceswith the flat top and bottom surfaces of adjacent coils in contactforming loop-shaped or eyelet-shaped filter pores. In the disclosedembodiment, the filter assembly includes a drive engaging the helicalcoil, wherein the drive moves adjacent coils relative to each other,thereby modifying and accurately controlling a volume or area of theloop-shaped filter pores to filter fluids having contaminants ofdifferent sizes, for example. In one preferred embodiment, the volume ofthe loop-shaped filter pores between adjacent coils have essentially thesame shape and volume during filtering, but the shape and volume of thefilter pores may be changed by the drive to filter different fluids in aprecise controlled manner and enlarged during backwashing.

In one embodiment, the drive rotates at least one of the coils relativeto a remainder of the coils, thereby sliding the opposed flat top andbottom surfaces of adjacent coils relative to each other into and out ofregistry, thereby controlling the shape and volume of the loop-shapedfilter pores. In an alternative embodiment, the drive is driven againstan end of the helical coil to compress or expand the helical coil,thereby reducing or expanding the volume of the loop-shaped filterpores. Alternatively, as disclosed in this application, theseembodiments may be combined. In a still further embodiment, the filterassembly includes a pneumatic piston driven against an end of thehelical coil retaining the coils in a predetermined orientation, whereinthe pneumatic piston is released to rapidly increase the volume of theloop-shaped filter pores during backwashing. The pneumatic piston mayalso be used in combination with a rotary drive which, as describedabove, rotates at least one of the coils relative to a remainder of thecoils to bring the sinusoidal cycles or waves into and out of registry.In one preferred embodiment, the cylindrical helical coil of the filterassembly is formed of a resilient stiff metal, such as stainless steel,such that the volume of all of the loop-shaped filter pores are changedsimultaneously to have the same volume. Following filtration, thepneumatic piston may be retracted, quickly expanding the loop-shapedfilter pores for backwashing.

In one disclosed embodiment, the continuous resilient cylindricalhelical coil is formed of stainless steel, which has several advantagesin filtering waste fluids including increased life and reduced corrosionas will be understood by those skilled in this art. However, the helicalcoil may also be formed of other steels and Hastaloys, for example. Thepreferred number of sinusoidal cycles for each coil will depend upon theapplication. However, a helical coil having three to ten sinusoidalcycles per coil has been found to be suitable for most applications ofthe filter assembly of this invention. Although the helical coil of thefilter assembly of this invention is preferably resilient, it shouldalso be relatively stiff having a width of 3 to 6 mm and a thickness ofbetween 0.4 mm and 2 mm.

In the disclosed embodiment having a helical or rotary drive, the rotarydrive may rotate at least one of the coils relative to the remainingcoils, such that the sinusoidal cycles of adjacent coils are in fullregistry, such that the volume of the loop-shaped pores between adjacentcoils is reduced to essentially zero. In this embodiment, at least oneof the flat top and bottom surfaces include radial grooves providingflow of fluids into or out of the continuous resilient cylindricalhelical coil and filtering of fluids into the submicron pore size. Forexample, the grooves may have a depth of between 0.1 mm and 1 micron orless. The diameter of the cylindrical helical coil will also depend uponthe application. However, a helical coil having an outside diameter of16 mm to 30 mm has been found suitable for most applications. Finally,the width of the loop-shaped filter pores will also depend upon theapplication for the filter assembly. However, a continuous resilientcylindrical helical coil having loop-shaped filter pores having a widthof 0.5 mm when the crest of adjacent coils are in contact has been foundsuitable for most applications.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1A is a side view of a filter assembly illustrating a plurality offiltration apertures defined between crests and troughs of adjacent wavecoils of a filter element of the assembly;

FIG. 1B is a perspective view of the filter element of the assemblyillustrating the plurality of wave coils arranged axially and definingan inner cavity;

FIG. 2A is an enlarged side view of a portion of the filter element;

FIG. 2B is an enlarged side view of a wave coil having crests andtroughs;

FIGS. 3A through 3C are side views of various shearing surfaces of wavecoils including a plurality of ridges for enhancing shear forcesimparted on a fluid that is to be filtered;

FIG. 4 is an exploded perspective view of the filter assembly incombination with a canister for filtering the fluid;

FIG. 5A is a partially cross-sectional side view of the filter assemblyillustrating an inlet valve disposed at an inlet of the filter canisterand an outlet valve disposed at an outlet of the filter canister;

FIG. 5B is a schematic representation of a backwash position of theinlet valve at the inlet of the filter canister;

FIG. 6A is a partially cross-sectional side view of the filter assemblydisposed in the filter canister illustrating an alternative adjustmentmechanism including a manual adjustment assembly for modifying a lengthL of the filter element to reduce and expand the filtration apertures;

FIG. 6B is an enlarged, partially cross-sectional view of the manualadjustment assembly that may be utilized in the adjustment mechanism;

FIG. 7 is a partially cross-sectional side view of the filter assemblydisposed in the filter canister illustrating a further alternativeadjustment mechanism including a motor for automatically modifying thelength L of the filter element to automatically reduce and expand thefiltration apertures;

FIG. 8A is an exploded perspective view of two filter assemblies in anested configuration where one filter assembly is disposedconcentrically about another filter assembly;

FIG. 8B is an enlarged perspective view of a baffle cage included in thenested configuration of FIG. 8A where individual baffles are hollow suchthat a filtration additive can be delivered to the filtration apertures;

FIG. 9 is a schematic view of filter assemblies arranged in parallel andin series and illustrating a controller in communication with the filterassemblies;

FIG. 10A is a schematic view of the fluid flowing through an inside ofthe inner cavity such that a filtrate of the fluid flows through thefiltration apertures and through an outside of the inner cavity, and aretentate of the fluid is retained on the inside of the inner cavity;

FIG. 10B is a schematic view of the fluid flowing through the outside ofthe inner cavity such that the filtrate of the fluid flows through thefiltration apertures and through the inside of the inner cavity, and theretentate of the fluid is retained on the outside of the inner cavity;

FIG. 11 is a partially cross-sectioned side view of a further embodimentof a filter assembly with the filter element fully expanded;

FIG. 12 is a partial side cross-sectional view of the filter assemblyshown in FIG. 11 with the coils of the filter elements in registry andsubstantially compressed;

FIG. 13 is a partial top perspective view of the filter element shown inFIGS. 11 and 12;

FIG. 14 is a partial side view of the expanded filter element as shownin FIG. 11;

FIG. 15 is a partial side view of the filter element as shown in FIG. 14with the filter coils partially in registry, reducing the size of thefilter pores; and

FIG. 16 is a partial side view of the filter element shown in FIGS. 14and 15 with the filter coils in registry as shown in FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the Figures, wherein like numerals indicate like orcorresponding parts throughout the several views, a filter assembly forfiltering a fluid is generally disclosed at 10. It is to be understoodthat the filter assembly 10 and method of filtering according to thesubject invention are capable of filtering both liquids and gases as thefluid. The filter assembly 10 of the subject invention is mostpreferably used to filter fluids having solid particles including, butnot limited to, slurries of biological waste. As such, the filterassembly 10 is commonly used in combination with such devices as shakerscreens, steam scrubbers and/or strippers, biofilters, conveyors, and asa component in mobile filtration units.

As shown best in FIGS. 1A through 2B, the filter assembly 10 includes aplurality of wave coils 12. The plurality of wave coils 12 are formedfrom individual flat wave coils 12. The wave coils 12 include at leastone crest 14 and at least one trough 16 and are arranged axially todefine a filter element 18. Although the wave coils 12 need only includeone crest 14 and one trough 16, the wave coils 12 preferably includemore than one crest 14 and more than one trough 16 and will be describedas such below.

The filter element 18 includes first 20 and second 22 ends and an innercavity 24. The filter element 18 also includes a length L extendingbetween the first and second ends 20, 22. The filter assembly 10 of thesubject invention incorporates at least one retention post 26, as shownin FIG. 4, that extends through the inner cavity 24 and between thefirst and second ends 20, 22 of the filter element 18 to maintain theaxial arrangement of the wave coils 12. The first end 20 of the filterelement 18, as disclosed throughout the Figures, is a bottom end 20 ofthe filter element 18, and the second end 22 of the filter element 18,as disclosed throughout the Figures, is a top end 22 of the filterelement 18. Therefore, the subject description will continue only withreference to the top and bottom ends 20, 22 of the filter element 18.However, the description of the first and second ends 20, 22 of thefilter element 18 is not intended to be limiting, and it is to beunderstood that the first and second ends 20, 22 of the filter element18 could also be a left and right end of the filter element 18. Also,the diameter, the length L, and the stiffness of the filter element 18may vary.

As shown in the Figures, the wave coils 12 that define the filterelement 18 are preferably a wave spring. As such, the wave coils 12preferably extend continuously in an endless path through the crests 14and troughs 16 and between the first and second ends 20, 22 of thefilter element 18. It is to be understood that the wave coils 12 are notrequired to extend continuously. That is, although not preferred, thesubject invention may include connecting members, not shown in theFigures, that connect each of the wave coils 12 together. In thisembodiment, the wave coils 12 can be said to be segmented. Also, in thepreferred embodiment, the wave coils 12 actually extend continuously ina helix through the endless path between the first and second ends 20,22.

Referring now to FIGS. 3A through 3C, the wave coils 12 include ashearing surface 28. The shearing surface 28 imparts shear forces on thefluid as the fluid is being filtered. Preferably, the shearing surfaces28 of the wave coils 12 include a plurality of ridges 30 to enhance theshear forces imparted on the fluid being filtered. As shown in FIGS. 3Athrough 3C, the ridges 30 may be of varying shapes and sizes dependingon the purpose for the filter assembly 10. For instance, if shearing ofthe fluid is the primary purpose, then the ridges 30 having sharp,cone-shaped teeth, as shown in FIG. 3C are ideal. Preferably, the ridges30 are laser-etched both transversely and sequentially along the wavecoils 12, and the ridges 30 are machined to ridge depths on the wavecoils 12 of from hundredths of millimicrons to microns. Alternatively,the ridges 30 may be photo-etched.

It is not required that the wave coils 12 be only flat or ridged forshearing purposes. That is, although not preferred, the wave coils 12may even be formed from round or smooth stock. Furthermore, the wavecoils 12 may include a coating for modifying the flow of the fluid beingfiltered. That is, the wave coils 12 may be coated to adsorb or to repelsolutes in the fluid. Such coatings include, but are not limited to,magnetic coatings, hydrophilic coatings, hydrophobic coatings, andspecific affinity coatings such as antibodies which have a specificaffinity toward a particular antigen such as PCBs. The coatings canassist the wave coils 12 in performing ‘micro-filtration’ when thefiltration apertures are at a 0 micron filtration aperture 34 size,which is described below. The hydrophobic coating is particularly usefulthroughout industrial applications for the filtering of water, oil, andwater/oil mixtures.

The filter assembly 10 also includes a support 32 that engages one ofthe bottom and top ends 20, 22 of the filter element 18 for supportingthe wave coils 12. That is, the support 32 engages either the bottom end20 or top end 22. The support 32 also diverts the fluid inside oroutside of the inner cavity 24 of the filter element 18. In other words,the support 32 also diverts the fluid to one of the inside and outsideof the inner cavity 24. Depending on the embodiment, the support 32functions to divert the fluid inside the inner cavity 24 or to divertthe fluid outside the inner cavity 24. The support 32 will be describedin further detail below.

The crests 14 of one wave coil 12 engage the trough 16 of an adjacentwave coil 12 to define at least one filtration aperture 34, or afiltration pore, between each crest 14 and each trough 16 of theadjacent wave coils 12. Preferably the filtration aperture 34 isspindle-shaped as disclosed throughout the Figures. In a preferredembodiment, the filter element 18 is 2.25 inches in diameter, the lengthL is 5 inches, the filter element 18 includes 100 wave coils 12, andeach wave coil 12 engages the adjacent wave coil 12 three and one-halftimes per 360°. Of course, the number of times each wave coil 12 engagesthe adjacent wave coil 12 can vary. It is to be understood that, withthe exception of FIG. 1A, the crests 14 and troughs 16, as well as theat least one filtration aperture 34 defined therebetween, aresignificantly exaggerated for the descriptive and illustrative purposesof subject invention. As disclosed throughout the Figures, the subjectinvention preferably includes a plurality of filtration apertures 34,and the subject invention will be described below in terms of theplurality of filtration apertures 34 although more than one filtrationaperture 34 is not necessarily required.

The fluid that is diverted by the support 32 is filtered through thefiltration apertures 34. This will be described below. For now, if, forexample, the filtration apertures 34 had a crest 14-to-trough 16separation of 500 microns, then any particulates suspended within thefluid that are less than 500 microns will pass through the filtrationapertures 34 as a filtrate 36 of the fluid, and any particulatessuspended within the fluid that are greater or equal to 500 microns willbe retained on the filter element 18 as a retentate 38, or filter cake,of the fluid.

Referring primarily to FIGS. 4 through 7, the filter assembly 10 of thesubject invention further includes an adjustment mechanism 40. Morespecifically, the adjustment mechanism 40 engages at least one of thebottom and top ends 20, 22 of the filter element 18 for modifying thelength L, extending between the first and second ends 20, 22 of thefilter element 18, to reduce and expand the at least one filtrationaperture 34 or the filtration apertures 34. Therefore, the filtrationapertures 34 are variably-size filtration aperture 34 because they areadjustable or tunable by the adjustment mechanism 40. The filtrationapertures 34 are adjustable, depending on process requirements and thecharacteristics of the filter element 18, specifically of the wave coils12, between a maximum filtration aperture 34 size and a 0 micronfiltration aperture 34 size. The length L is increased to expand the atleast one filtration aperture 34, or to allow the crests 14 and troughs16 to decompress, and the length L is decreased to reduce the at leastone filtration aperture 34, or to compress the crests 14 and troughs 16.Although the adjustment mechanism 40 varies depending on the embodiment,the adjustment mechanism 40 is preferably at least partially disposed inthe inner cavity 24 of the filter element 18.

The adjustment mechanism 40 includes a base plate 42 engaging one of thebottom and top ends 20, 22 of the filter element 18. As shown in FIG. 4,the base plate 42 preferably engages the bottom end 20 of the filterelement 18. The support 32, introduced above, is further defined as thebase plate 42. As such, the base plate 42 supports the wave coils 12 andalso diverts the fluid inside or outside of the inner cavity 24 forfiltering. As understood by those skilled in the art, in the embodimentwhere the fluid is first diverted inside of the inner cavity 24, asshown in FIG. 10A, the base plate 42 is preferably a doughnut-shapedplate surrounding the filter element 18 that blocks the outside of theinner cavity 24 such that the fluid can only flow into the inside of theinner cavity 24.

The base plate 42 includes a base collar 44 and a platform 46 extendingfrom the collar 44. The platform 46 of the base plate 42 is at leastpartially disposed in the inner cavity 24 of the filter element 18. Inthis position, the platform 46 operates to keep the base plate 42 inengagement with either the bottom end 20 or top end 22 of the filterelement 18. The wave coils 12 of the filter element 18 are preferablyanchored to the platform 46. A shoulder portion 48 of the base plate 42is defined between the base collar 44 and the platform 46. The shoulderportion 48 of the base plate 42 actually supports one of the bottom andtop ends 20, 22 of the filter element 18. As shown in FIGS. 4 and 5A,the shoulder portion 48 supports the bottom end 20 of the filter element18.

In the preferred embodiment, the adjustment mechanism 40 furtherincludes a flange member 50 that engages the other of the bottom and topends 20, 22 of the filter element 18 relative to the base plate 42. Theflange member 50, as described in greater detail below, is adjustablyengaged relative to the base plate 42 for modifying the length L. Assuch, the filtration apertures 34 can be reduced and expanded.

The flange member 50 more specifically includes a flange collar 52 and ayoke 54. The yoke 54 extends from the collar 52 toward the base plate42. Preferably, the yoke 54 is integrally molded with the flange collar52 and includes a yoke base segment 56 that is described below. The yoke54 of the flange member 50 is at least partially disposed in the innercavity 24 of the filter element 18 to keep the flange member 50 inengagement with the other of the bottom and top ends 20, 22 of thefilter element 18 relative to the base plate 42. That is, the yoke 54keeps the flange member 50 in engagement with the top end 22 of thefilter element 18. A shoulder portion 58 of the flange member 50 isdefined between the flange collar 52 and the yoke 54. The shoulderportion 58 of the flange member 50 supports the other of the bottom andtop ends 20, 22 of the filter element 18 relative to the base plate 42.That is, the shoulder portion 58 of the flange member 50 supports thetop end 22 of the filter element 18.

The adjustment mechanism 40 more specifically includes at least onepilot spring 60, preferably a compression spring. As will be describedbelow, the pilot spring 60 subjects the filter assembly 10 to a loadingpressure by biasing the flange member 50. The pilot spring 60 issupported on the yoke 54 of the flange member 50. More specifically, thepilot spring 60 is supported on the base segment 56 of the yoke 54 andis further supported by first and second washers 61, 63. The basesegment 56 of the yoke 54 defines an opening, not numbered, and thepilot spring 60 is supported on the base segment 56 of the yoke 54 aboutthe opening. In this position, the pilot spring 60 biases the flangemember 50 to decrease the length L of the filter element 18 and reducethe filtration apertures 34, and the pilot spring 60 biases the flangemember 50 to increase the length L of the filter element 18 and expandthe filtration apertures 34.

The adjustment mechanism 40 of the filter assembly 10 further includesan adjustment shaft 62. As disclosed throughout the Figures, theadjustment shaft 62 extends from the base plate 42 to engage the flangemember 50 such that the flange member 50 is adjustable relative to thebase plate 42. More specifically, the adjustment shaft 62 extends fromthe base plate 42 through the opening and the pilot spring 60 to engagethe flange member 50 such that the flange member 50 is adjustablerelative to the base plate 42. As such, the length L of the filterelement 18, as described above, can be modified. Preferably, theadjustment shaft 62 extends from the base plate 42 though the innercavity 24 of the filter element 18 to engage the flange member 50. Alsoin the preferred embodiment, the adjustment shaft 62 is threaded and isintegrally molded with the base plate 42. It is to be understood thatthe adjustment shaft 62 may alternatively include locking teeth ordetents, as opposed to threads. In certain embodiments of the subjectinvention, the adjustment shaft 62 can be rendered electromagnetic suchthat the wave coils 12 are magnetically-induced by the adjustment shaft62 to adsorb a fluid having magnetic particles. This electro-magnetizedadjustment shaft 62 is preferably used throughout various medicalapplications including, but not limited to, blood separationapplications where cellular and viral components are removed from bloodusing magnetic antibodies.

To make the flange member 50 adjustable relative to the base plate 42,the subject invention includes an adjustable lock 64 that engages theadjustment shaft 62. More specifically, the adjustable lock 64 isdisposed on the adjustment shaft 62, adjacent the spring 60 and oppositethe base segment 56 of the flange member 50, for adjusting the flangemember 50 relative to the base plate 42 to modify the length L.Manipulation of the adjustable lock 64 directly causes the spring 60 tobias the flange member 50. In the preferred embodiment, the adjustablelock 64 is a threaded adjustment nut 66 that is disposed on the threadedadjustment shaft 62. In alternative embodiments, the adjustable lock 64may be designed to engage and lock locking teeth or detents on theadjustment shaft 62. As shown in FIG. 4, a set screw 68 may extendthrough the adjustable lock 64 to the adjustment shaft 62 to ensure thatthe adjustable lock 64 is locked on the adjustment shaft 62 forretaining the flange member 50 in an adjusted position relative to thebase plate 42.

When operating the adjustable lock 64 to reduce the filtration apertures34, the lock is tightened on the adjustment shaft 62. The pilot spring60 exerts a compressive force on the flange member 50 which, in turn,exerts a compressive force on the filter element 18. As understood bythose skilled in the art, the strength of the pilot spring 60, i.e., theweight required to compress the pilot spring 60, must exceed thestrength of the wave coils 12, i.e., the weight required to compress thewave coils 12, that define the filter element 18. For example, thestrength of the pilot spring 60 could be 32 pounds and the strength ofthe wave coils 12 could be 25 pounds. In such an example, when theadjustable lock 64 is tightened, pressure is applied to the strongerpilot spring 60 which transfers the compressive pressure to the weakerwave coils 12 of the filter element 18 thereby reducing the filtrationapertures 34. The opposite occurs when the adjustable lock 64 isloosened on the adjustment shaft 62. The reduction and expansion of thefiltration apertures 34 may be calibrated by developing a linear plot ofthe rotations of the adjustable lock 64 versus the size of thefiltration apertures 34.

In alternative embodiments of the subject invention, disclosed in FIGS.6A, 6B, and 7, the adjustment mechanism 40 varies. Referring now to FIG.6A, the flange member 50 only includes a flange collar 52, i.e., theyoke 54 is not a functioning component of the flange member 50. Instead,the flange collar 52 acts as a fixed plate, not numbered, engaging theother of the bottom and top ends 20, 22 of the filter element 18relative to the base plate 42. That is, in this embodiment, the fixedplate engages the top end 22 of the filter element 18. In thisembodiment, the flange member 50 also includes a sliding plate 70, alsoknown as a floating plate. As described in the orientation disclosed inFIG. 6A, the sliding plate 70 is disposed between the base plate 42 andthe fixed plate. The base plate 42 is adjustable. More specifically, thesliding plate 70 is supported above the base plate 42 by one or morepilot springs 60. The sliding plate 70 is adjustably engaged relative tothe fixed plate for modifying the length L of the filter element 18 toreduce and expand the filtration apertures 34. Preferably, the slidingplate 70 is adjustable relative to the fixed plate along side posts 71which may, or may not be, the same as the retention posts 26.Preferably, a controller 72, as shown in FIG. 9, is in communicationwith the sliding plate 70 of this alternative adjustment mechanism 40 toautomatically adjust the sliding plate 70 relative to the fixed plate.Other functions of the controller 72 will be described below.

In contrast to automatic adjustment accomplished, in part, with thecontroller 72, a manual adjustment assembly 74, shown generally in FIG.6A and more specifically in FIG. 6B, may be used to modify the length Lof the filter element 18. More specifically, the manual adjustmentassembly 74. The assembly 74 includes an adjustment handle 76. Theadjustment handle 76 rotates a handle adjustment nut 78, preferably apacking nut. The adjustment handle 76, through rotation of the handleadjustment nut 78, contacts a packing spring 80 to advance or pull-backa drive rod 82. As shown in the Figures, the drive rod 82 is in directcontact with the base plate 42 and is in indirect contact with thesliding plate 70 via the pilot springs 60. Of course, it is to beunderstood that a number of turns of the adjustment handle 76 can becorrelated to the size of the filtration apertures 34.

Referring now to FIG. 7, the subject invention includes a motor 84,selectively activated by the controller 72, refer to FIG. 9, toautomatically adjust the adjustment mechanism 40. It is to be understoodthat the motor 84 can be selectively activated by the controller 72 inresponse to various forms of data including, but not limited to, flowdata, pressure data, solids loading data, time data, and particle sizedistribution data. In the alternative embodiment for the adjustmentmechanism 40 disclosed in FIG. 7, the sliding plate 70 is eliminated aswell as the pilot springs 60. Instead, the drive rod 82 of theadjustment mechanism 40 is rigidly fixed, as through a weld or screwend, directly to the base plate 42 that supports the filter element 18.The base plate 42 is adjustable. In this embodiment, referred to as‘direct drive,’ the motor 82 preferably has two settings, a maximumsetting for controlling the size of the filtration apertures 34 duringfiltering, and a minimum setting for expanding the filtration apertures34 during automatic backwashing, which is described below. Of course, ineither of the embodiments disclosed in FIGS. 6A and 7, the manualadjustment assembly 74 and the motor for automatically adjusting theadjustment mechanism 40 can be interchanged.

The filter assembly 10 of the subject invention is utilized incombination with a filter canister 86. The filter canister 86 includesan inlet 88 for receiving the fluid to be filtered and an outlet 90 fordelivering the fluid that has been filtered. As shown in FIG. 5A, theinlet 88 of the filter canister 86 is preferably oval-shaped to impart avortex onto the fluid received into the filter canister 86 forfiltering. The vortex imparted by the oval-shaped inlet 88 is effectivein exposing the fluid to the filter element 18. The vortex alsomaintains the retentate 38 toward an inner wall 92 of the filtercanister 86 and away from the filtration apertures 34 as long aspossible. The canister 86 may also include internal blades, baffles, andthe like to encourage a vortex and more effectively expose the fluid tothe filter element 18.

The filter assembly 10, and in particular the filter element 18 of thefilter assembly 10, is disposed in the filter canister 86. Morespecifically, the filter canister 86 includes a shelf 94 for supportingthe filter assembly 10 in the filter canister 86. A gasket 96, such asan O-ring, is disposed about the flange member 50 to mate with the shelf94 of the filter canister 86. As such, the outlet 90 of the filtercanister 86 is sealed from the inlet 88 of the filter canister 86. Morespecifically, the flange collar 52 of the flange member 50 includes amachined depression 98. The gasket 96 is disposed in the machineddepression 98 to ensure that the filter assembly 10 fits tightly intothe shelf 94 of the filter canister 86. The gasket 96 presses againstthe inner wall 92 of the filter canister 86 such that outlet 90 of thefilter canister 86 is sealed from the inlet 88 of the filter canister86. Furthermore, a plurality of fastening screws 100 extend through theflange collar 52 and into threaded inserts 102 in the shelf 94 of thefilter canister 86. Once the filter element 18 and flange member 50,including the flange collar 52, are inserted into the filter canister86, the fastening screws 100 are tightened to rigidly maintain thefilter assembly 10 on the shelf 94. Rigid maintenance of the filterassembly 10 on the shelf 94 ensures that the outlet 90 and inlet 88 ofthe filter canister 86 are sealed, resists movement of the filterassembly 10 during activation of the adjustment mechanism 40 to modifythe length L, and resists movement of the filter assembly 10 duringautomatic backwashing of the filter assembly 10, which is describedbelow.

Referring now to FIGS. 8A, 8B, and 9, the subject invention preferablyincorporates a plurality of the filter assemblies 10. The plurality offilter assemblies 10 are disclosed in a nested configuration in FIGS. 8Aand 8B. That is, at least one filter assembly 10 included in theplurality of filter assemblies 10 is disposed concentrically aboutanother filter assembly 10 of the plurality. In this nestedconfiguration, a coarse filter assembly 10A is disposed within a finefilter assembly 10B. Of course, it is to be understood that any numberof filter assemblies 10 may be nested with each other.

This embodiment also includes baffle cages 104 that support at least onebaffle 106. The baffle cages 104, supporting the baffles 106, aredisposed within the inner cavity 24 of the filter element 18 of aparticular filter assembly 10. The baffles 106 provide structuralsupport to the filter elements 18 and are preferably angled so as todirect the fluid that is being filtered toward the filtration apertures34. As shown in FIG. 8B, the baffles 106 are preferably hollow such thata filtration additive can be delivered to the filtration apertures 34through the baffles 106. One suitable filtration additive, steam,enhances the filtering, or other stripping, of the fluid that is beingfiltered. Other suitable filtration additives include oxygen forbioprocessing capabilities. Additionally, a plurality of beads 108 maybe disposed within the inner cavities 24 of the filter elements 18 forincreasing a surface area of the fluid that is exposed for filtering.The beads 108 are preferably used in combination with baffles 106 thatare hollow because the beads 108 are particularly effective in exposingthe fluid to be filtered to the filtration additive.

As shown in FIG. 9, the filter assemblies 10 can be arranged in parallelP and/or in series S depending on various process requirements. Theplurality of filter assemblies 10 can also be arranged in a pyramidsequence. The purpose of the pyramid sequence is to utilize more thanone filter assembly 10 having different filtration aperture 34 sizes tosegregate coarse solid particles from intermediate and fine solidparticles where the filtration apertures 34 would otherwise becomeimmediately ‘blinded.’ The pyramid sequence is represented in FIG. 9 bythe filtration aperture 34 sizes of 125 microns, 50 microns, and 25microns. Of course, it is to be understood that such a pyramid sequencemay be continuously altered to accommodate suspended particle sizedistribution and also to equalize flow rates across the filterassemblies 10.

As shown schematically in FIG. 9, the controller 72 is in communicationwith the filter assemblies 10, in particular with the adjustmentmechanisms 40 of each filter assembly 10. The controller 72 is also incommunication with pressure 110, temperature 112, and flow sensors 114,and with the valves, shown schematically, in FIG. 9. The adjustmentmechanism 40 can automatically modify the length L of the filter element18 to automatically reduce and expand the filtration apertures 34 asneeded. The automatic modification of the length L is primarilyfacilitated by at least one pressure sensor 110 that is in communicationwith the controller 72. The pressure sensor 110 communicates with thecontroller 72, and the controller 72 activates the adjustment mechanism40, preferably through the motor 84, to automatically reduce and expandthe filtration apertures 34.

As shown in FIGS. 5A, 5B, 6A, 7, and 9, an inlet valve 116 is disposedat the inlet 88 of the filter canister 86 and an outlet valve 118 isdisposed at the outlet 90 of the filter canister 86. The outlet valve118 will be described further below. The inlet valve 116 isolates thefilter canister 86 from the fluid to be filtered when necessary such asupon automatic backwashing as described below. The controller 72 is incommunication with the inlet valve 116 to open and close the valve 116and accomplish this isolation. Referring to FIGS. 5A and 5B, the inletvalve 116 is preferably a three-way inlet valve 116. In a filteringposition of the three-way inlet valve 116, as disclosed in FIG. 5A, theinlet valve 116 allows the fluid that is to be filtered to flow throughthe valve 116 and into the inlet 88 of the filter canister 86 forfiltering. However, in a backwash position 120 of the three-way inletvalve, as disclosed in FIG. 5B, the inlet valve 116 isolates the filtercanister 86 from the fluid to be filtered. Instead, as will be describedbelow, the retentate 38 of the fluid is able to flow through the inletvalve 116 when the inlet valve 116 is in the backwash position 120.

Preferably, there is a first pressure sensor 122 disposed at the inlet88 of the filter canister 86 and a second pressure sensor 124 disposedat the outlet 90 of the filter canister 86. The first pressure sensor122 determines an inlet pressure and the second pressure sensor 124determines an outlet pressure. The first and second pressure sensors122, 124 are in communication with the controller 72. A differencebetween the inlet pressure and the outlet pressure, which can bedetermined by the controller 72, establishes a pressure differential. Inreliance on this pressure differential, the controller 72 can activatethe inlet valve 116 to isolate the filter canister 86 from the fluid tobe filtered. More specifically, the controller 72 can activate the inletvalve 116 to isolate the filter canister 86 when the outlet pressure isless than the inlet pressure by a predetermined amount.

The method of filtering the fluid according to the subject inventionincludes the step of flowing the fluid toward the support 32 of thefilter assembly 10. In the context of the preferred embodiment, thefluid flows toward the base plate 42 of the adjustment mechanism 40operating as the support 32. The base plate 42 diverts the fluid insideor outside the inner cavity 24 of the filter element 18. Once inside oroutside the inner cavity 24, the diverted fluid is filtered through thefiltration apertures 34 defined between the crests 14 and the troughs16. As such, the filtrate 36 of the fluid passes through one of theinside or outside of the inner cavity 24 and the retentate 38 of thefluid is retained on the other of the inside or outside of the innercavity 24 relative to the filtrate 36. That is, the filtrate 36 passesthrough either the inside or outside of the inner cavity 24 and theretentate 38 is retained on the opposite side of the inner cavity 24 ofthe filter element 18 relative to the filtrate 36.

Referring now to FIG. 10A, if the fluid flows toward the base plate 42and is diverted to the inside of the inner cavity 24 and then throughthe filtration apertures 34, then the filtrate 36 of the fluid, whichalso flows through the filtration apertures 34, passes through theoutside of the inner cavity 24 to the outlet 90 of the filter canister86, and the retentate 38 of the fluid, which cannot flow through thefiltration apertures 34, is retained on the inside of the inner cavity24 of the filter element 18. As described above, in this embodiment, thebase plate 42 is preferably the doughnut-shaped plate surrounding thefilter element 18 that blocks the outside of the inner cavity 24 suchthat the fluid can only flow into the inside of the inner cavity 24.Alternatively, as shown in FIG. 10B, if the fluid flows toward the baseplate 42 and is diverted to the outside of the inner cavity 24 and thenthrough the filtration apertures 34, then the filtrate 36 of the fluidflows through the filtration apertures 34 and passes through the insideof the inner cavity 24 to the outlet 90 of the filter canister 86,whereas the retentate 38 of the fluid is retained on the outside of theinner cavity 24 of the filter element 18.

The method of filtering utilizing the filter assembly 10 according tothe subject invention also includes the step of adjusting the filterassembly 10 to reduce and expand the filtration apertures 34. It is tobe understood that the step of adjusting the filter assembly 10 ispreferably accomplished with the adjustment mechanism 40 incommunication with the pressure sensor or sensors 110, 122, 124 and thecontroller 72 as described above.

The method further includes the step of cleaning the filter assembly 10.The most preferred manner in which to clean the filter assembly 10 is byautomatically backwashing the filter assembly 10 by momentarilyreversing the flow of the filtrate 36, or another fluid, as describedimmediately below. To automatically backwash the filter assembly 10, thefilter assembly 10 is isolated from the fluid to be filtered. To isolatethe filter assembly 10 from the fluid to be filtered, the inlet valve116 at the inlet 88 of the filter canister 86 is closed. In thepreferred embodiment, the inlet valve 116 is activated into the backwashposition 120. Once the filter assembly 10 is isolated from the fluid tobe filtered, the filtrating apertures 34 are expanded. The filtrationapertures 34 may be expanded at regularly-defined time intervals oraccording to other process parameters as described above. However, thefiltration apertures 34 are preferably automatically expanded inresponse to the pressure differential between the bottom and top ends20, 22 of the filter element 18. That is, the filtration apertures 34are preferably automatically expanded when the pressure differentialexceeds the predetermined amount such as when the outlet pressure isless than the inlet pressure by the predetermined amount. Once thefilter assembly 10 is isolated, the adjustment mechanism 40 increasesthe length L of the filter element 18 to expand the filtration apertures34. In the most preferred embodiment, the threaded adjustment nut 66 isautomatically loosened on the threaded adjustment shaft 62 and thelength L of the filter element 18 automatically expands.

Once the filtration apertures 34 are expanded, the flow of the fluidthat has been filtered, i.e., the filtrate 36, is reversed such that thefiltrate 36 flows back through the filtration apertures 34 and theretentate 38 of the fluid is automatically dislodged from the inside orthe outside of the inner cavity 24, depending on the embodiment. It isalso to be understood that the flow of the filtrate 36 may be reversedat the same time, or even before, the filtration apertures 34 areexpanded. Of course, as the retentate 38 is automatically dislodged, thebackwash position 120 of the preferred three-way inlet valve allows thedislodged retentate 38 to flow to a retentate 38 collection reservoirthat collects the backwashed retentate 38. Once the filter assembly 10is clean, the flow of the filtrate 36 returns to normal.

Alternatively, the outlet valve 118 at the outlet 90 of the filtercanister 86 may be a three-way outlet valve 118, similar to thethree-way inlet valve 116. As such, this three way outlet valve 118 canbe manipulated to a position such that a second fluid, distinct from thefluid that has been filtered, i.e., the filtrate 36, can be utilized toflow back through the filtration apertures 34 to automatically backwashthe filter assembly 10 by dislodging the retentate 38. In thissituation, the filtrate 36 is not used to automatically backwash thefilter assembly 10. In this embodiment, the three-way outlet valve 118allows the filter canister 86 to selectively receive fluid forback-washing the filter element 18 when the outlet pressure is less thanthe inlet pressure by the predetermined amount as communicated by thecontroller 72.

FIGS. 11 to 16 illustrate a further embodiment of the filter assembly210 of this invention which may be utilized to perform the methods offiltration described above. The filter assembly 210 shown in FIGS. 11and 12 includes a filter element 212 comprising a continuous cylindricalhelical coil having a plurality of circular interconnected helical coils214 as best shown in FIG. 13 and described above, each circular helicalcoil having a plurality of regular sinusoidal wave form or shapeincluding peaks and troughs as shown in FIG. 13. The peaks “p” andtroughs “t” of adjacent coils 214 are in contact to provide enlarged“loop-shaped” or eyelet-shaped filter pores between adjacent coils asshown in FIG. 14, or the peaks “p” and troughs “t” of adjacent coils 214may be aligned as shown for example in FIG. 16 as described below.

The filter assembly 210 shown in FIGS. 11 and 12 includes a lowerhousing 218 having an inlet 220 and an outlet 222 for receiving a fluidstream to be filtered, such as a waste gas or liquid stream as describedabove. The filter assembly 210 further includes a cover 224 which issupported on the lower housing member 218 by circumferentially spacedinner and outer retention posts 226 and 228, respectively. A filtrationchamber 230 is defined between the lower housing member 218 and thecover 224 by a cylindrical housing wall 232. Thus a fluid streamreceived through inlet 220 is received under pressure in the filtrationchamber 230 for filtration by the filter element 212. The fluid streamincluding contaminants is then received through the filter pores or theradial grooves as described below through the filter element 212 intothe axial center of the filter element 212 and the filtrated fluid isthen discharged through the outlet 222. As described above, theparticles, molecules or material removed by the filter element areremoved by backwashing as further described below.

The disclosed embodiment of the filter assembly 210 shown in FIGS. 11and 12 further includes a pneumatic cylinder 234 attached to andsupported on the cover 224 of the housing having an air inlet 236 and anair outlet 238. A piston assembly 240 is reciprocally supported in thepneumatic cylinder or chamber 234 including a piston head 242 having anO-ring 244, such that the piston assembly 240 is sealingly supportedwithin the pneumatic cylinder 234. The piston assembly 240 has a stroke“S” as shown in FIG. 11. Pneumatic pressure supplied through air inlet236 of the pneumatic cylinder 234 will thus drive the piston assembly240 downwardly from the position shown in FIG. 11 to the position shownin FIG. 12 as described in more detail hereinbelow.

In the disclosed embodiment, the filter assembly 210 further includes adrive assembly engaging the helical coil filter element 212 movingadjacent coils 214, thereby modifying and controlling a volume of theloop-shaped filter pores between adjacent coils as now described. In thedisclosed embodiment, the filter assembly 210 includes a stepper motor246 attached to and supported by the upper end of the piston assembly240 as shown in FIGS. 11 and 12. As will be understood by those skilledin this art, a stepper motor is a brushless, synchronous electric motorthat can divide a full rotation into a large number of steps. Whencommutated electronically, the motor's position can be controlledprecisely, without any feedback mechanism. Although a stepper motor hasseveral advantages for this application, any other type of rotary drivemay also be utilized. The driveshaft 248 of the stepper motor 246 isconnected in the disclosed embodiment to an upper end of the cylindricalhelical filter element 212 to relatively rotate the filter coils toaccurately control the volume of the loop-shaped filter pores 260 asdescribed below. The driveshaft 248 of the stepper motor 246 in thedisclosed embodiment is connected to a coupling 250 as shown in FIGS. 11and 12. A shaft 252 connected to the coupling 250 is connected to aclamp assembly connected to the upper end of the filter element 212. Thelower end of the filter element 212 is rigidly connected to the lowerhousing member 218 such that, upon rotation of the clamp assembly 254 bythe stepper motor 246, the coils 214 of the filter element 212 arerotated relative to each other as described below.

In the disclosed embodiment, the circular interconnected coils 214 ofthe filter element 212 are initially aligned crest or peak “p” to trough“t” as shown in FIG. 14 with the filter pores or openings 260 enlargedto their maximum. Alternatively, it would also be possible to initiallyalign the coils peak to peak and trough to trough. It is important tounderstand, however, that the width or amplitude of the sinusoidal waveor curve has been greatly exaggerated in FIGS. 11, 13 and 14 for abetter understanding of the filter assembly of this invention and themethod of filtration. As set forth above, the volume of the openings orloop-shaped filter pores 260 of the filter element 212 in the filterassembly of this invention may be accurately controlled to filterdifferent fluids. First, the piston assembly 240 may simply be extendedto compress the filter element, thereby reducing the size or volume ofthe filter pores 260 by supplying air under pressure through the inlet236 of the pneumatic cylinder 234. However, in one preferred embodiment,the drive 246 rotates at least one of the coils 214 relative to theremainder of the coils, thereby relatively sliding the opposed flat topand bottom surfaces of adjacent coils relative to each other into andout of registry, thereby accurately controlling the volume of theloop-shaped pores 260. Further, because the filter element 212 is formedof a stiff resilient metal, such as stainless steel, the loop-shapedfilter pores 260 are all modified simultaneously, such that all filterpores have essentially the same volume, which is important for accuratecontrol.

As best shown in FIG. 15, rotation of the upper coil of the continuouscylindrical helical coil filter element 212, by rotation of thedriveshaft 248 of the stepper motor 246 causes the peaks “p” of adjacentcoils to rotatably slide on the flat upper and lower surfaces 262relative to the remaining coils, reducing or expanding the apertures orfilter pores 260. Finally, as shown in FIG. 16, the sinusoidal-shapedcoils may be moved into full registry, such that the peaks “p” andtroughs “t” are fully aligned. Again, however, the spacing betweenadjacent coils 214 has been exaggerated in FIG. 16 for clarity. In fact,the adjacent coils may be in full contact, such that the filter pores260 between adjacent filter coils is reduced to essentially zero.However, in the disclosed embodiment, at least one of the opposed flatsurfaces 262 of the filter coils 214 includes circumferentially spacedradial grooves 264 permitting the flow of fluids through the filterelement when the filter pores 260 between adjacent coils are reduced tosubstantially zero. Thus the radial grooves 264 significantly increasethe applications for the filter assembly 210 of this invention.

Having described a further embodiment of the filter assembly 210 of thisinvention as shown in FIGS. 11 to 16, the operation of the filterassembly may now be described. In one preferred embodiment of the filterassembly of this invention, the filter element 212 is a continuouscylindrical resilient helical coil having a regular sinusoidal shapeincluding regular peaks “p” and troughs “t” as described above. Thefilter element may be formed of stainless steel, such as 316 stainlesssteel, which is stiff and resilient. However, the helical coil filterelement may also be formed of a Hastaloy or other steel. Anotheradvantage of stainless steel is corrosion resistance. The coilpreferably has flat top and bottom surfaces 262, such that the flatsurfaces of adjacent coils will slide against each other during rotationas best shown in FIGS. 14 to 16. A suitable thickness between the flattop and bottom surfaces 262 is 0.4 to 2 mm having a width of between 3and 6 mm. The preferred number of sinusoidal waves of each coil willdepend upon the application. However, it has been found that 3 and 10sinusoidal curves or waves for each coil 214 will be very suitable formost applications. Further, the “width” of the loop-shaped openings orfilter pores will also depend upon the application, but it has beenfound that filter pores having a maximum width of about 0.5 mm issuitable for most applications. Finally, the depth of the radial grooves264, which may be formed by laser etching, is preferably between 1μ to10 nanometers.

The filter assembly 210 is thus operated by adjusting the apertures orloop-shaped filter pores 260 to the desired volume for filtration byeither extending the shaft 252 using pneumatic pressure through inletport 236, driving the piston assembly 240 downwardly in FIG. 11 tocompress the coils against each other, thereby reducing the volume ofthe filter pores 260. However, in one preferred embodiment, the steppermotor 246 is simultaneously rotated to bring the peaks “p” and troughs“t” into and out of registry as shown, for example, in FIG. 15. Asdescribed above, rotation of the upper coil will simultaneously rotateall coils relative to the bottom coil because the filter element isformed of a stiff resilient material, such as 316 stainless steel. Thecoils may be rotated into full registry, as shown in FIG. 16, whereinthe filter pores are reduced to substantially zero, wherein the fluidflow is only through the radial grooves 264. The fluid to be filtered isthen received through the housing inlet 220 into the filter chamber 230and flows through the filter element 222 as shown in FIG. 12. As will beunderstood, the filter assembly may be used to filter almost any fluiddepending upon the filter pore size including, for example, residual,industrial and agricultural waste and sludges to produce, for example,potable water from waste and may be used for the clarification andrefinement of waste oil from waste water-oil mixtures, etc. Uponcompletion of the filtering process or when the filter element 212becomes clogged with the particles or media suspended in the fluid, thefilter element 212 may be easily flushed by opening the filter pores 260as shown in FIG. 11 and flushing solution is then received through theoutlet 222 and flushed through the filter element 212. In the disclosedembodiment, backwashing may be facilitated by rotating the stepper motorin the opposite direction from the direction used to compress the coils214 of the filter coil while maintaining the clamp assembly 254 in theextended position as shown in FIG. 12. Then, upon completion of thefiltering process, the filter element is “opened” by simply retractingthe clamp 254 to the open position shown in FIG. 11 which can beaccomplished in a second or two.

As will be understood, various modifications may be made to thedisclosed filter assembly and method of this invention within thepurview of the appended claims and the embodiments of the filterassembly disclosed herein are for illustrative purposes only. Forexample, as described above, any rotary and axial drive may be used formodifying and controlling the size of the loop-shaped filter pores 260,and the filter apparatus of this invention is not limited to the use ofa stepper motor or pneumatic drive.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation.Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. The invention may bepracticed otherwise than as specifically described within the scope ofthe appended claims. Furthermore, the reference numerals are merely forconvenience and are not in any way to be read as limiting.

1. A filter assembly, comprising: a continuous resilient cylindricalhelical coil including a plurality of interconnected circular helicalcoils, each circular coil having a regular sinusoidal-shape in thedirection of the helix, including opposed flat top and bottom surfaceswith said flat top and bottom surfaces of adjacent coils in contact andforming loop-shaped filter pores between adjacent circular helicalcoils.
 2. The filter assembly as defined in claim 1, wherein said filterassembly includes a drive engaging said helical coil, said drive movingadjacent circular helical coils relative to each other, therebyaccurately controlling and modifying a volume of said loop-shaped filterpores.
 3. The filter assembly as defined in claim 2, wherein said driverotates at least one of said circular helical coils relative to aremainder of said circular helical coils, thereby relatively slidingsaid opposed flat top and bottom surfaces of adjacent coils relative toeach other into and out of registry and accurately controlling saidvolume of said loop-shaped filter pores.
 4. The filter assembly asdefined in claim 2, wherein said drive is driven against an end of saidcylindrical helical coil to compress or expand said cylindrical helicalcoil, thereby reducing or expanding said volume of said loop-shapedfilter pores.
 5. The filter assembly as defined in claim 2, wherein saiddrive is capable of moving said sinusoidal-shaped helical coils into andout of registry, thereby reducing or expanding said volume of saidloop-shaped pores to essentially zero.
 6. The filter assembly as definedin claim 5, wherein at least one of said opposed flat top and bottomsurfaces of said helical coil includes radial grooves providing fluidflow through said grooves when said volume of said loop-shaped pores isreduced to essentially zero.
 7. The filter assembly as defined in claim6, wherein said radial grooves have a depth of between 0.1 mm and 1 nm.8. The filter assembly as defined in claim 1, wherein said resilienthelical coil is formed of stainless steel.
 9. The filter assembly asdefined in claim 1, wherein said resilient helical coil has a thicknessof between 0.4 mm and 2 mm.
 10. The filter assembly as defined in claim1, wherein said resilient helical coil has a width of between 3 mm and 6mm.
 11. A filter assembly for filtering fluids, comprising: a continuouscylindrical resilient helical filter coil, comprising a plurality ofinterconnected circular helical coils, each circular helical coil havinga regular sinusoidal shape in the direction of the helix includingopposed flat top and bottom surfaces, with said flat top and bottomsurfaces of adjacent circular coils in contact forming loop-shapedfilter pores between adjacent circular coils, and a drive engaging saidcylindrical helical filter coil, said drive moving adjacent circularhelical coils relative to each other, thereby modifying and controllinga volume of said loop-shaped filter pores.
 12. The filter assembling asdefined in claim 11, wherein said drive rotates at least one of saidcircular helical coils relative to a remainder of said circular helicalcoils, thereby relatively sliding said opposed flat top and bottomsurfaces of adjacent coils relative to each other into and out ofregistry and controlling said volume of said loop-shaped filter pores.13. The filter assembly as defined in claim 12, wherein said filterassembly includes a pneumatic piston driven against an end of saidcylindrical helical coil retaining said coils, then rapidly releasingsaid coils to increase said loop-shaped filter pores during backwash.14. The filter assembly as defined in claim 11, wherein one of saidopposed flat top and bottom surfaces of said helical coil includesradial grooves providing fluid flow through said grooves.
 15. The filterassembly as defined in claim 11, wherein said helical coil has athickness of between 0.4 mm and 2 mm.
 16. A filter assembly forfiltering fluids, comprising: a continuous resilient cylindrical helicalcoil having a regular sinusoidal shape in the direction of the helix,including opposed flat top and bottom surfaces with said flat top andbottom surfaces of adjacent coils in contact forming loop-shaped filterpores between adjacent coils, and a drive engaging said cylindricalhelical coil rotating at least one of said coils relative to a remainderof said coils, thereby relatively sliding said opposed flat top andbottom surfaces of adjacent coils aligning said sinusoidal portions ofsaid coils into and out of registry, thereby accurately controlling saidvolume of said loop-shaped filter pores between said coils.
 17. Thefilter assembly as defined in claim 16, wherein said continuousresilient helical coil is formed of stainless steel.
 18. The filterassembly as defined in claim 16, wherein said continuous resilientcylindrical helical coil has between 3 and 10 sinusoidal cycles percoil.
 19. The filter assembly as defined in claim 16, wherein saidhelical coil has a thickness of between 0.4 mm and 2 mm.
 20. The filterassembly as defined claim 16, wherein said flat top and bottom surfacesof said continuous resilient cylindrical helical coil has radial groovesproviding fluid flow through said grooves when said volume of saidloop-shaped pores is reduced.
 21. A filter assembly, comprising: acontinuous resilient cylindrical helical coil including a plurality ofinterconnected circular helical coils, each circular coil having aregular sinusoidal-shape in the direction of the helix, includingopposed flat top and bottom surfaces with said flat top and bottomsurfaces of adjacent coils in contact and forming loop-shaped filterpores between adjacent circular helical coils.
 22. The filter assemblyas defined in claim 21, wherein said filter assembly includes a driveengaging said helical coil, said drive moving adjacent circular helicalcoils relative to each other, thereby accurately controlling andmodifying a volume of said loop-shaped filter pores.
 23. The filterassembly as defined in claim 22, wherein said drive rotates at least oneof said circular helical coils relative to a remainder of said circularhelical coils, thereby relatively sliding said opposed flat top andbottom surfaces of adjacent coils relative to each other into and out ofregistry and accurately controlling said volume of said loop-shapedfilter pores.
 24. The filter assembly as defined in claim 22, whereinsaid drive is driven against an end of said cylindrical helical coil tocompress or expand said cylindrical helical coil, thereby reducing orexpanding said volume of said loop-shaped filter pores.
 25. The filterassembly as defined in claim 22, wherein said drive is capable of movingsaid sinusoidal-shaped helical coils into and out of registry, therebyreducing or expanding said volume of said loop-shaped pores toessentially zero.
 26. The filter assembly as defined in claim 25,wherein at least one of said opposed flat top and bottom surfaces ofsaid helical coil includes radial grooves providing fluid flow throughsaid grooves when said volume of said loop-shaped pores is reduced toessentially zero.
 27. The filter assembly as defined in claim 26,wherein said radial grooves have a depth of between 0.1 mm and 1 nm. 28.The filter assembly as defined in claim 21, wherein said resilienthelical coil is formed of stainless steel.
 29. The filter assembly asdefined in claim 21, wherein said resilient helical coil has a thicknessof between 0.4 mm and 2 mm.
 30. The filter assembly as defined in claim21, wherein said resilient helical coil has a width of between 3 mm and6 mm.
 31. A filter assembly for filtering fluids, comprising: acontinuous cylindrical resilient helical filter coil, comprising aplurality of interconnected circular helical coils, each circularhelical coil having a regular sinusoidal shape in the direction of thehelix including opposed flat top and bottom surfaces, with said flat topand bottom surfaces of adjacent circular coils in contact formingloop-shaped filter pores between adjacent circular coils, and a driveengaging said cylindrical helical filter coil, said drive movingadjacent circular helical coils relative to each other, therebymodifying and controlling a volume of said loop-shaped filter pores. 32.The filter assembling as defined in claim 31, wherein said drive rotatesat least one of said circular helical coils relative to a remainder ofsaid circular helical coils, thereby relatively sliding said opposedflat top and bottom surfaces of adjacent coils relative to each otherinto and out of registry and controlling said volume of said loop-shapedfilter pores.
 33. The filter assembly as defined in claim 32, whereinsaid filter assembly includes a pneumatic piston driven against an endof said cylindrical helical coil retaining said coils, then rapidlyreleasing said coils to increase said loop-shaped filter pores duringbackwash.
 34. The filter assembly as defined in claim 31, wherein one ofsaid opposed flat top and bottom surfaces of said helical coil includesradial grooves providing fluid flow through said grooves.
 35. The filterassembly as defined in claim 31, wherein said helical coil has athickness of between 0.4 mm and 2 mm.
 36. A filter assembly forfiltering fluids, comprising: a continuous resilient cylindrical helicalcoil having a regular sinusoidal shape in the direction of the helix,including opposed flat top and bottom surfaces with said flat top andbottom surfaces of adjacent coils in contact forming loop-shaped filterpores between adjacent coils, and a drive engaging said cylindricalhelical coil rotating at least one of said coils relative to a remainderof said coils, thereby relatively sliding said opposed flat top andbottom surfaces of adjacent coils aligning said sinusoidal portions ofsaid coils into and out of registry, thereby accurately controlling saidvolume of said loop-shaped filter pores between said coils.
 37. Thefilter assembly as defined in claim 36, wherein said continuousresilient helical coil is formed of stainless steel.
 38. The filterassembly as defined in claim 36, wherein said continuous resilientcylindrical helical coil has between 3 and 10 sinusoidal cycles percoil.
 39. The filter assembly as defined in claim 36, wherein saidhelical coil has a thickness of between 0.4 mm and 2 mm.
 40. The filterassembly as defined claim 39, wherein said flat top and bottom surfacesof said continuous resilient cylindrical helical coil has radial groovesproviding fluid flow through said grooves when said volume of saidloop-shaped pores is reduced.